Search results for "phoretic"
showing 10 items of 59 documents
A Monte Carlo Study of Knots in Long Double-Stranded DNA Chains.
2016
We determine knotting probabilities and typical sizes of knots in double-stranded DNA for chains of up to half a million base pairs with computer simulations of a coarse-grained bead-stick model: Single trefoil knots and composite knots which include at least one trefoil as a prime factor are shown to be common in DNA chains exceeding 250,000 base pairs, assuming physiologically relevant salt conditions. The analysis is motivated by the emergence of DNA nanopore sequencing technology, as knots are a potential cause of erroneous nucleotide reads in nanopore sequencing devices and may severely limit read lengths in the foreseeable future. Even though our coarse-grained model is only based on …
Novel cationic copolymers of a polyasparthylhydrazide: synthesis and characterization.
2005
Alpha,beta-poly(asparthylhydrazide) (PAHy), a water soluble synthetic polymer, was functionalized by using EDCI chemistry with 3-(carboxypropyl)trimethyl-ammonium chloride (CPTACl) obtaining carboxypropyltrimethyl ammonium copolymers (PAHy-CPTA). Three PAHy-CPTA copolymers at increasing derivatization degrees (38%, 48%, 58%) were chosen for subsequent investigations. The capability of these copolymers to bind, neutralize, and protect DNA against degradation by DNase II was evalued by gel retardation assay and DNA degradation test at pH 5.5. Zeta potential measurements show that all studied polymers are able to neutralize the anionic charge of DNA at polymer/DNA weight ratio in the range of …
Resveratrol, a polyphenolic phytoalexin present in red wine, enhances expression and activity of endothelial nitric oxide synthase.
2002
Background— Estrogens can upregulate endothelial nitric oxide synthase (eNOS) in human endothelial cells by increasing eNOS promoter activity and enhancing the binding activity of the transcription factor Sp1. Resveratrol, a polyphenolic phytoalexin found in grapes and wine, has been reported to act as an agonist at the estrogen receptor. Therefore, we tested the effect of this putative phytoestrogen on eNOS expression in human endothelial cells. Methods and Results— Incubation of human umbilical vein endothelial cells (HUVEC) and HUVEC-derived EA.hy 926 cells with resveratrol for 24 to 72 hours upregulated eNOS mRNA expression in a time- and concentration-dependent manner (up to 2.8-fold)…
Analysis of Specific Protein-DNA Interactions
1998
The central issue in the regulation of genome functions is the mechanism of sequence-specific protein-nucleic acid interactions. Gene expression, replication, recombination and DNA condensation in chromatin are steered by binding of regulatory protein ligands to specific sites in DNA. Numerous methods have been developed to study protein-DNA interactions. In this chapter we discuss two widely used and straightforward approaches to address this problem.
A Functional Role of IκB-ε in Endothelial Cell Activation
2000
Abstract The NF-κB inhibitor IκB-ε is a new member of the IκB protein family, but its functional role in regulating NF-κB-mediated induction of adhesion molecule expression is unknown. In vascular endothelial cells, IκB-ε associates predominantly with the NF-κB subunit Rel A and to a lesser extent with c-Rel, whereas IκB-α and IκB-β associate with Rel A only. Following stimulation with TNF-α, pyrrolidine dithiocarbamate (PDTC), N-acetylcysteine, and dexamethasone prevented IκB kinase-induced IκB-α, but not IκB-β or IκB-ε phosphorylation and degradation. Since the activation of NF-κB is required for the induction of adhesion molecule expression, we examined the role of IκB-ε in the transacti…
Polysaccharide/polyaminoacid composite scaffolds for modified DNA release.
2009
Abstract In this work composite polymeric films or sponges, based on hyaluronic acid (HA) covalently crosslinked with α,β-poly(N-2-hydroxyethyl)(2-aminoethylcarbamate)- d , l -aspartamide (PE), have been prepared and characterized as local gene delivery systems. In particular, HA/PE scaffolds have been loaded with PE/DNA interpolyelectrolyte complexes, employing PE as a macromolecular crosslinker for HA and as a non-viral vector for DNA. In vitro studies showed that HA/PE films and sponges have high compatibility with human dermal fibroblasts and they give a sustained DNA release, whose trend can be easily tailored by varying the crosslinking ratio between HA and PE. Electrophoresis analysi…
Nitric oxide increases the decay of matrix metalloproteinase 9 mRNA by inhibiting the expression of mRNA-stabilizing factor HuR.
2003
Dysregulation of extracellular matrix turnover is an important feature of many inflammatory processes. Rat renal mesangial cells express high levels of matrix metalloproteinase 9 (MMP-9) in response to inflammatory cytokines such as interleukin-1 beta. We demonstrate that NO does strongly destabilize MMP-9 mRNA, since different luciferase reporter gene constructs containing the MMP-9 3' untranslated region (UTR) displayed significant reduced luciferase activity in response to the presence of NO. Moreover, by use of an in vitro degradation assay we found that the cytoplasmic fractions of NO-treated cells contained a higher capacity to degrade MMP-9 transcripts than those obtained from contro…
Analysis of involvement of the 3?-untranslated regions in regulating mRNA stability for vitellogenin, cyanoprotein ?, and cyanoprotein ? from the bea…
2002
The degradation of the 3'-untranslated regions (UTRs) of vitellogenin, cyanoprotein alpha, and cyanoprotein beta from the bean bug, Riptortus clavatus, was analyzed in vitro. The degradation pattern was similar for all three RNAs, with a high degradation rate in non-diapausing adult insects and no degradation in the fifth instar nymphs and in diapausing adults, and was not correlated with the expression levels of these three proteins. Proteins binding to the 3'-UTRs were detected in polysomal and cytosolic extracts. These factors, however, were present in all developmental stages. The abundance of the polysomal factor showed little variation, but the cytosolic factor was enriched in adult i…
Anti-inflammatory Function of High-Density Lipoproteins via Autophagy of IκB Kinase
2015
Background & Aims: Plasma levels of high-density lipoprotein (HDL) cholesterol are frequently found decreased in patients with inflammatory bowel disease (IBD). Therefore, and because HDL exerts anti-inflammatory activities, we investigated whether HDL and its major protein component apolipoprotein A-I (apoA-I) modulate mucosal inflammatory responses in vitro and in vivo. Methods: The human intestinal epithelial cell line T84 was used as the in vitro model for measuring the effects of HDL on the expression and secretion of tumor necrosis factor (TNF), interleukin-8 (IL-8), and intracellular adhesion molecule (ICAM). Nuclear factor-κB (NF-κB)-responsive promoter activity was studied by …
Functional characterization of the sea urchin sns chromatin insulator in erythroid cells.
2005
Abstract Chromatin insulators are regulatory elements that determine domains of genetic functions. We have previously described the characterization of a 265 bp insulator element, termed sns, localized at the 3′ end of the early histone H2A gene of the sea urchin Paracentrotus lividus. This sequence contains three cis-acting elements (Box A, Box B, and Box C + T) all needed for the enhancer-blocking activity in both sea urchin and human cells. The goal of this study was to further characterize the sea urchin sns insulator in the erythroid environment. We employed colony assays in human (K562) and mouse (MEL) erythroid cell lines. We tested the capability of sns to interfere with the communi…